Roof mounted bike carriers are widely used. Such bike carriers typically comprised a rail on which the bike is supported as well as a fixation mechanism for fixing the bike in an upright condition. Such bike carriers are typically constructed to support a single bike. Furthermore, the bike carriers are constructed so as to be mountable on a load carrier system mounted on the roof of a vehicle. Such load carrier systems typically comprise two crossbars which are mountable to the roof of the vehicle cross to the vehicle's longitudinal direction. It is possible, to mount multiple bike carriers next to each other on the cross bars of such load carrier systems.
Focus has been put on the construction of such bike carriers in order to enhance the mountability of bikes thereon, in particular with respect to bike supporting devices which are able to support the bike in one of different regions of the bike and which are coupled to the wheel tray. As such bike supporting devices, single-sided arms for holding a bicycle frame are known. Such single-sided arms allow the mounting of a bicycle from only one side of the wheel tray. Therefore, mechanisms have been provided which allow an inverted application of the single-sided arms with respect to the wheel tray. However, the known mechanisms are rather complex and the actions to be taken by a user for invertedly providing the single-sided arms is time consuming and annoying for each bike carrier.